Improvement in safety-valves for steam-boilers



ANDREW J. PRESCOTT.

Improvement in Safety Valves of Steam Boilers.

Patented Dec.5,1871.

Witnessers: QMZQ UNITED STATES ANDREW J. PRESCOTT, OF OATAWISSA, PENNSYLVANIA.

IMPROVEMENT IN SAFETY-VALVES FOR STEAM-BOILERS.

Specification forming part of Letters Patent N 0. 121,659, dated December 5, 1871.

To all whom it may concern:

Be it known that I, ANDREW J. PRESCOTT, of Gatawissa, in the county of Columbia and in the State of Pennsylvania, have invented certain new and useful Improvements in Safety-Valves for Steam-Boilers; and I do hereby declare that the tollowing is a full, clear, and exact description thereof, reference being had to the accompanying drawing and to the letters of reference marked thereon making a part of this specification.

The nature of my invention consists in the construction and arrangement of a safetywalve for steam-boilers, as will be hereinafter more fully set forth.

In order to enable others skilled in the art to which my invention appertains to make and use the same, I will now proceed to describe its construction and operation, referring to the annexed drawing, in which Figure 1 is a side view; Fig. 2, a longitudinal vertical section; and Fig. 3,21 bottom view of my valve. Figure 4 is a View of the upper end of a locking spring used in my safety-valve.

A represents the valve, constructed as shown, the lower part being ball-shaped and the upper part tapering. This valve is seated in a cup or chamber, B, and over the valve is the concaved cap 0 and. cage E combined. The cap 0 is for the purpose of using the escaped steam to assist to close the valve when the steam falls below the standard amount the valve is set for. The cage E is for the purpose of confining the spring L, which is tightened down by the set-screw F in the upper part of the cage E to any desired amount. Around the spring L is a casing or tube, D, to prevent the steam from blowing on the same. 011 the set-screw F is a lock-nut, H, which fastens the set-screw so that it cannot be moved when the catch-spring G is made fast. This spring has on its upper end a projection, a, which tits in recesses or notches made in the outer circumference of the lock-nut H, and said spring is fastened to the cup B and cage E byseal-screws I) 0. These screwshave holesthroughtheir heads for the passage of a Wire or twisted wires, (I, the ends of which are to be connected by a seal, 0. Thus, when the valve is once set it cannot be changed except by breaking the seal. Around the cup or chamber B is a flange, J, with suitable holes for the purpose of bolting the valve to the boiler.

Havin gthus fully described In y invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The combination of the nut H, notched or recessed on its outer side, the catch-spring G with projection a, screws 1) b, wire or wires d, and

seal 0, all substantially as and for the purposes herein set forth.

2. The combination of the balland-taper valve A cup B, concave cap 0, cage E, spring-case I), nut H, and catch-spring G, all constructed and arranged substantially as and for the purposes herein set forth.

In testimony that I claim the foregoing l have hereunto set my hand this 14th day of October, 1871.

ANDREW J. PRESCOTT. 

